Process of producing tungsten oxide from tungsten ores



Patented Feb. rafters.

entree stares theater KDJI narrow, or roxYo-ru', JArAN, ASSIGNOR 'ro MITSUBISHI xoero xannsnrar KAISHA, or rox'ro, JAPAN, A conroaa'rronor JAPAN.

TROCESS 0F PRODUCING TUNGSTEN OXIDE FROM TUNGSTEN GEES.

Ito brewing.

To all whom it may concern:

Be it known that l, KoJi. AnJow, a subject of the Empire of Japan, residing at No. 1281 Minami-shi.uagawa-juku, Shinagawamachi, Ebara-gun, Tokyo-tn, Japan, have invented new and useful Improvements in Processes of Producing Tungsten Oxide from Tungsten Ores, of which the followin i is a specification.

his invention relates to a process of producing tungsten oxides from tungsten ores and involves the use of dilute sulphuric acid with or without pressure in a closed vessel.

The object of my invention is to carry out the prooessof making metal, alloys, hydroxide, oxide or any other compounds of tungsten in commercially pure state from tungsten ores in the most economical way without any technical difficulty unavoidable in the process hitherto-,known.

The use of sulphuric. acid for the decomposition of tungsten'ores is generally known but its operation has hitherto been done by the use of more or less concentrated sulphuric acid in an open vessel. The process is uneconomical, troublesome and even dangerous, as is described. and criticized fully in the following.

As is well known, tungsten ores are very stable and are not acted upon by sulphuric acid at temperatures below 100 'centigrade. At temperatures considerably higher than 100 centigrade, the decomposition sets in. Its decomposition, therefore, has hitherto been done by the use of concentrated sulphuric acid or a mixture of this acid and other salts in order to raise the temperature of the system sufficiently highv to complete the reaction. These old processes not only consumed great amount of chemicals and fuels, therefore, exceedingly uneconomical, but also are accompanied by two unavoidable technical dilfi'culties. Que of the difliculties is that the reaction products are ditficultly soluble in the concentrated sulphuric acid, and therefore, the reaction stops as soon as the particles of the ores are I covered by the films of the decomposition products. This gives rise to incomplete decomposition,

separating the reaction products from undecomposed ores and waste of materials and labour. Theother diiliculty in carrying out the old processes lies in the fact that the charged materials are under the condition troublesome operation for Application filed April 26, 1923. Serial No. 634,924.

to the evolution of suffocating fume containing sulphur oxides and even dangerous owing to the spitting of hot concentrated sulphuric acid.

I have now discovered that dilute sulphuric acid is the most powerful decomposition agent and that the tungsten ores are easily acted upon by it giving rise to the hydrated oxide of tungsten, without any technical difficulty or trouble during the oporation.

ln carrying out my invention, 1 take tungsten ores in a state of fine powder, charge them in a closed vessel with suiticieut amount of dilute sulphuric acid and continue stirring while heating. As the decomposition is carried out in a closed vessel, any temperature can be applied without difiiculty and danger of suffocating gas and spitting acid. The reaction products do not form insoluble films upon ores, therefore, the reaction proceeds speedily and completely to the end. The stirring of the reaction system, moreover, can be done most easily and most effectively and there is no marked tendency that the oreparticles settle down at the bottom of the vessel during the stirring.

Another useful feature of my invention lies in the fact that common impurities such as iron and manganese go easily and completely into the solution during the reaction and therefore by simple washing they are easily and completely excluded from tungsten oxides. This is not the case in the old processes, as the reaction products of these impurities are difiicultly soluble in the concentrated sulphuric acid forming hard solid films upon ores and even by repeated Washing it is diflicult to remove the last trace of these impurities. Other impurities such as tin, silicon and calcium may also be easily excluded by further treatment with which win show haw she pmcsss ks carried mph. 1 i0 110% W15 howevs t0 limit myself to these sxsmpias, it is easy i0 attain ths same ob isvt by changing one or more parts of His mples.

and (me at the paiwdsred are. are

and one; pm; of the powdsred 01's charged in an :uiisclavs, whirl: is provided with s stirmr and acid pionflining'. While stiz's'ing ii, heated h steam or dirct ."i1'- to 189 fientigizide under pressure. by which iireatmenfi iron and migranese in the Ewe compisizsiy mnwi'ted into soiubls sulphates, Affisr Irmif an hour cram "cut; in this wsy, the mixtureblown out inio :1 sewing sank and the clear ssiution is than dsmmisti of? The soiutinn can has aised repsstsdly for the treatment of the next charge of the powdsrsri ()Fb. To she settiefi mass, Water is added and. While stirring it is rsmoved inis swsshing tank, in with is is Washed rspeaissi'iy with 'Wsi'sr untii the Washed water bemmes ainmst neutral. The washed material is then filiersci anti dried mid wmmerciaiiy pure i'u'ngstic oxide is ihus obtained. hundred p: of this mwdereo'i nxiris'am'i fiheen pa powdered nhsrsnal :im ihoirmighly mixmi anci piacsd in an iron crucible. This is filmed at 1209" centig'rads smi cnmmercisl Insist-Hie 'ungstsn is thus obtained.

It can be used for the prspm'ation of tungstan alloys.

Znthe Way as exampie 1, powfisrsii "ivei'i mmii's is treated Wick the diluteas? phm-ic acid and the dsmmpossd. mas, flioroughly Washed and filters and. (him? at 150 centigisds.

in 011162 to remove tin, silica or other im purgitiss, if any such is presszmthe hyflmted tungsten mfide is di soived in di' Inte ammonia Water by warming, the sslw tion fiitsmci and evziperstsd. The my I of pure ammaniuin tungstaie rims obtsmsii sre then wasted. We Qbtain in this Way "pm-s {Qffij} tungsten. exide. "When i" reduced by hydrogen as i grads pure meta-Hie tungsten which can be useii f0:- th's preparatien of electric lamp filtimsnt.

Example 3.

Yrepsrs fine pewdsr mt" sheeiits, as fins as 1/5200 millimeter 01" sven finer. Time's parts 1i,l5% {by whims} suiphuric said Ms which pi" "sided a stii'iez' and mil? pmoi 'Whfls 1g it heated my sizszim or dire zi' fizii (hinged in mi ziiiinciavs,

4 .3"; maven hour hw'imeni in tune is aim-:11 02:1. in clear sfiluti-i n is tbs gses; 1 phai-si mining; s tsiiied.

as cium U'HZHX'H."

i. A. p:

b11981, WHILE 141i vessel 11mm? 0% 5mm, amm nia, shsrsmi Tin tesummy in: mis 

